1. Field of the Invention
This invention relates to a photo-curing hollow structure, which expands by injection of fluid and is cured by light such as sunlight and the like to form a hollow molded structure, and a method of curing the same.
2. Description of the Related Art
In an emergency due to natural or man-made disasters, there are cases where temporary housing such as prefabricated houses and tents are set up, to aid victims thereof. In such cases, many setup materials such as columns, panels and tents prefabricated in factories are carried by trucks and the like, and they are assembled and installed on the spot.
However, the larger scale the prefabricated houses and tents have, the more number of parts of the setup materials they requires. Further, the sizes of the columns and panels thereof increase, and it is troublesome to store, carry, and assemble and install them in the field. In particular, it is troublesome to carry materials to places, access to which is difficult, such as intermontane areas and remote areas.
Further, with respect to outdoor installation equipments, such as various play equipments installed in playgrounds and playland and the like, products molded in the aimed shapes in factories in advance are carried by trucks or the like and assembled and installed in the field. Also in this kind of things, those large-sized are voluminous and the installation work thereof, such as transportation, is troublesome.
A photo-curing hollow structure which has solved the above problem are registered as the Japanese Patent No. 2916330 (filed on Aug. 31, 1992). This structure is formed as a semi-finished product in the aimed shape when it is unused. Since photo-curing resin impregnated into a base material layer of the photo-curing hollow structure has flexibility in a gel state, the structure is stored in compact form in a storage bag or a case, in the state of being folded or rolled up small. Therefore, it can be kept in a warehouse and carried very easily, in the unvoluminous state.
When it is used, the photo-curing hollow structure is taken out from the storage bag or case in the field. Then, the whole structure is quickly swollen by injecting gas or water by a compressor or a proper gas generator into an internal bag layer thereof. Then, the structure is subjected to direct sunlight or light of an artificial light source, while being maintained in the swollen state. Thereby, the light permeates a translucent outer layer on the periphery of the structure, and impinges on the photo-curing resin in the base material layer. Exposed to the light, the photo-curing resin is cured and the base material layer is set, and thereby the structure is changed to a hollow molded structure having a predetermined shape for the intended purpose. The hollow molded structure can be installed and used as it is, or after extracting the injected fluid, such as water.
The structure can be stored and carried very easily and reduce the costs. Further, when it is used, it can be installed and used as a hollow molded structure of a predetermined shape suitable for its purpose by a very simple work in the installation field for a short time.
An extension structure of a space structure is registered as Japanese Patent No. 2728081 (filed on Apr. 15, 1996). This invention has an extendable extension part which extends a space structure, such as an antenna and a solar-cell paddle in a spacecraft, and is fixed onto the spacecraft. The extension part is made of shape memory alloy, which is stored in the spacecraft when the spacecraft is launched, and extends by heat of sunlight in the space after launching. Further, the surface of hull of the extension part is coated with a UV-curing resin.
However, the structure has a problem that the photo-curing resin sealed in its base-material layer is localized due to gravity. Specifically, while the hollow structure is stored or transported, the uncured photo-curing resin is collected in the bottom of the structure due to gravity. Therefore, it may occur also in transportation means in which the structure has a high acceleration, such as when it is released from a transport, launched with a rocket, or landed on another celestial body. Further, if curing is performed with sunlight, the structure has a problem that it has a difference in the curing speed between the front and the back due to the difference in temperature between them. Specifically, photo-curing resins are cured by exposing them to light. If the resin is cured outdoors or in the space with sunlight, it is rare that the resin is uniformly exposed to sunlight, and consequently the difference in the temperature between the front and the back increases. Further, in some kinds of photo-curing resins, curing is accelerated by temperature. Therefore, difference in the curing speed increases by the difference in the temperature in addition to the difference in exposure to light, and the whole structure may be distorted.
The present invention has been made in view of the above circumstances. An object of the present invention is to provide a photo-curing hollow structure which can inhibit localization of its photo-curing resin due to gravity and form a hollow molded structure having a predetermined shape suitable for its purpose.
Another object of the present invention is to provide a method of curing a photo-curing hollow structure, in which both end portions of the photo-curing hollow structure are rotatably supported, the photo-curing hollow structure is rotated during a curing process, direct sunlight or light of an artificial light source is uniformly transmitted through an outer layer, and thereby the whole structure can be cured almost simultaneously.